Elbow and Forearm Joint
Brachioradialis
-Inserts onto radius, affected by forearm position -Active contraction moves forearm to neutral -Strongest midway ↔ sup/pron and with speed in neutral
Pronator teres
-Similar line of pull as brachialis but only ½ as thick- affects forearm position
brachialis
-Strongest elbow flexor -Inserts onto ulna not affected by forearm position -Not affected by shoulder position
Max force for a muscle
10% longer than its resting length, due to elastic recoil of tissue adds to force production
Humeroulnar joint
Hinge joint 1 plane of motion
what deg of flexion contracture severely limits function
30 deg
Spinal cord injury named for
last level working
Varus
lateral collateral ligaments
Distal radioulnar joint stability by
Disk between distal ends Ant. and post. radioulnar ligaments bind the bones together Pronator Quadratus and ECU Interosseous Membrane
pronator quadratus
Distal Most active and consistent, not affected by elbow position, always on not affected by elbow position
Anconeus
First muscle to activate and maintain low levels of extension extends and stabilizes pulls capsule out of the way
Radial deviation
Flexor Carpi Radialis + ECRL/ECRB
Elbow
Allows relative shortening or lengthening of the UE for UE function and proper placement of the hand
lateral epicondyle
Attachments of joint capsule, ligaments, superficial extensors
medial epicondyle
Attachments of joint capsule, ligaments, superficial flexors
proximal radioulnar joint
Between fovea of radius and capitulum of ulna Aids in resisting valgus forces
Muscle of flexion
Brachialis Biceps Brachii Brachioradialis Pronator teres
ulnar deviation
Flexor carpi ulnaris + Extensor carpi ulnaris
triceps brachii
Medial and lateral cross only elbow long head cross shoulder forearm doesn't affect strength
Distal humerus landmarks
Medial epicondyles Lateral epicondyles Trochlea Capitulum Coronoid fossa Radial fossa
Biceps Brachii
More active when supinated Affected by shoulder and forearm position
Supinator
Origin on lat. epicondyle and lat. collateral and annular ligs. Minimal attachment to humerus, essentially no moment arm for flexion Elbow angle and speed of motion at the elbow don't affect the strength of this muscle Always on
annular ligament
Originates from ulna, loose attachemnts to capsule fibrocartilage- more solid less elastic primary restraint against radial dislocation( distraction)
Tennis elbow
Pain and weakness during resisted forearm supination and wrist extension Radial deviation Pain/tenderness in lateral epicondyle weakened grip
golfer's elbow
Pain, and weakness during resisted forearm pronation and wrist flexion Ulnar deviation Pain/tenderness in medial epicondyle
elbow flexion
Palmaris longus pronator teres Flexor carpi radialis flexor carpi ulnaris
Internal rotation paired with
Pronation
Pronation
Pronator Teres Pronator Quadratus Aided by: FCR Palmaris Longus Brachioradialis (if coming from full supination)
proximal Radius Landmarks
Radial head radial tuberosity
Biceps
Recruited if more force is needed Extremely strong supinator esp. with elbow flexed 90 deg
pronator teres
Two heads: humeral and ulnar Likely area of median n. compression: Pronator Teres Syndrome Strong pronator- similar to carpal tunnel syndrome, can see atrophy in thenar
Lateral collateral
attaches to lateral epicondyle and annular ligament weaker than MCL
Motion in a plane and around a
axis
pronation
bones criss crossed
supination
both parralel
Radius articulates with
capitulum
interosseous membrane transmits
compression forces
Rotation at elbow
conjunct
Fine motor control requires
distal mobility from proximal stability
mobility of proximal musculature to prevent injury
distally
Carrying angle of the arm
due to bony congruency 5 deg in M 10-15 deg in W use less energy for hand to mouth movement
Wrist extension
extensor carpi radialis longus extensor carpi radialis brevis extensor carpi ulnaris extensor digitorum extensor digiti minimi supinator
Passive locking requires
full ROM of extension
Valgus
medial collateral ligaments
what tricep fibers draw posterior capsule tight
medial fibers
which head of triceps is recruited first
medial, then lateral then long
Synergistically joint
motion work together to give function
active insufficiency
muscle that crosses two or more joints muscle shortened over every muscle it crosses low end of LT curve
Active for
neurological screening
Radial and Ulnar deviation require
neutralizers to create the frontal plane motion
elbow one of fastest to freeze
often ends up lacking 10-15 deg of extension after immobilization
Proximal Ulna Landmarks
olecranon coronoid process trochlea notch- hyaline cartillage
Humneroradial
plane, pivot or modified ball and socket
Which muscle has median nerve run through it
pronator teres
Valgus test
pushing inside to out
Varus test
pushing outside to in
Only muscle that insert where affect forearm position
radius
most force on fall goes to
radius IM transmits force to ulna
UCL and RCL
resist distraction
Closed kinetic chain
reversed muscle action
Passive elbow extension needs
shoulder flexion
how to reach out further
shoulder flexion rotate trunk side bend if stuck at 30 deg no compensating will affect
Muscles of extension
stabilizers during CKC role in functional transfers
if triceps not working
stack body on itself post delt pulls arm back pec minor pull scapula down
Passive for
stretching
External rotation paired with
supination
Supination or pronation what is stronger
supination bigger muscle longer pull
Supination muscles
supinator biceps brachii Aided by: Wrist extensors EPL, EI Brachioradialis (if coming from full pronation)- to neutral only
MCL
triangle shaped more resistance to force
olecranon articulates with
trochlea
radius rolls on
ulna
Joint capsule
weak anterior and posterior reinforced medially and laterally
Causes of insufficiency
weakness due to sarcomeres not being able to contract anymore
passive insufficiency
when a 2 joint muscle is lengthened over both joints
